Work will proceed under three headings: (1) An enzyme that dehydrogenates pyridoxine to pyridoxal will be purified from several sources and its substrate specificity determined. The equilibrium position of this enzyme is entirely toward pyridoxine formation; its true function is unknown, and we hope to eludicate it. (2) The three monophosphoric acid esters of pyridoxine are being synthesized proparatory to comparing carefully their hydrolytic behavior in the presence of acids, alkalis and various phosphatases. (3) The mechanism of uptake of vitamin B6 and of pantothenic acid by bacterial cells is different according to the species examined and is being further studied. BIBLIOGRAPHIC REFERENCES: Teller, J.H., Powers, S.G., and Snell, E.E. Ketopantoate hydroxymethyltransferase. I. Purification and role in pantothenate biosynthesis. J. Biol. Chem., 251, 3780-3785 (1976). Powers, S.G., and Snell, E.E. Ketopantoate hydroxymethyltransferase. II. Physical, catalytic, and regulatory properties. J. Biol. Chem. 251, 3786-3793 (1976).